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From Thomas Neidhart <thomas.neidh...@gmail.com>
Subject Re: [math] random boolean arrays
Date Sun, 12 Jul 2015 09:50:10 GMT
On 07/11/2015 09:43 PM, Phil Steitz wrote:
> On 7/11/15 12:29 PM, Thomas Neidhart wrote:
>> On 07/11/2015 09:08 PM, Phil Steitz wrote:
>>> The code implemented in MATH-1242 to improve performance of KS
>>> monteCarloP in-lines efficient generation of random boolean arrays.
>>>   Unfortunately, I think the implementation is not quite random (see
>>> comments on the ticket).  To verify it, we need to be able to test
>>> the random boolean array generation directly.  To do that, we have
>>> to either expose the method (at least as protected) in the KS class
>>> or add it somewhere else.  I propose the latter but am not sure
>>> where to put it.  For speed, we need to avoid array copies, so the
>>> API will have to be something like randomize(boolean[], nTrue).  It
>>> could go in the swelling MathArrays class, or RandomDataGenerator. 
>>> The latter probably makes more sense, but the API does not fit too
>>> well.  Any ideas?
>> If it is just for testing purposes, you can also access the method in
>> question via reflection, see an example here:
>> http://stackoverflow.com/questions/34571/how-to-test-a-class-that-has-private-methods-fields-or-inner-classes
> 
> Do you think it *should* be a private method of the K-S class?

Right now, I do not see much uses outside the class, but if we decide to
make it public then I would prefer a special util class in the random
package to avoid cluttering the MathArrays class.

Regarding the RandomDataGenerator: I think this class should be
deprecated and replaced by a Sampler interface as proposed by Gilles.
One can then create a sampler for any distribution or from other
sources, e.g. when needing a fast and efficient sampler without
replacement (see MATH-1239).

I did not have time to complete a patch, but am working on it.

Thomas

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